This invention relates generally to bicycles, and relates more particularly to locking mechanisms for preventing the theft of bicycles.
Numerous different types of locking mechanisms and devices have been proposed and used through the years to combat bicycle thefts, ranging from a simple chain-and-padlock device to a variety of different mechanisms for attachment to or incorporation in a bicycle. One general approach is to prevent turning of one of the wheels (for examples, see U.S. Pat. Nos. 4,180,998 and 563,991), and another is to prevent steering of the front wheel (for examples, see U.S. Pat. Nos. 2,625,813, 608,080 and 605,981).
In a typical bicycle, the front wheel is mounted in a fork that is supported on the front end of the frame by an upright "head tube", and is steered by means of a handlebar that is disposed above the head tube and connected to the fork through the head tube. Usually, the fork and the handlebar are connected by telescoping stems forming a steering connection that is rotatably mounted in bearings in the head tube. The head tube is supported on at least one frame strut, usually a so-called "down tube" that is inclined downwardly and rearwardly above the front wheel, and frequently by an upper generally horizontal strut as well, a so-called "top tube" that makes a "V" with the down tube.
When a padlock and chain are used to lock the bicycle, the chain typically is passed through a wheel and around part of the frame, and sometimes around a fixed object as well so that the bicycle cannot be carried away. Since much of the problem of bicycle theft is attributable to thieves who ride away on the stolen bicycle, simply locking a wheel to the frame is sufficient to discourage most thieves, except those who carry tools to cut chains or padlocks.
In prior locking mechanisms that were designed to lock the front wheel assembly against steering, means have been provided for locking the fork to the frame, sometimes using a key lock for the ease and convenience obtained with such a lock. These have not found commercial acceptance, however, perhaps because of their relatively complicated construction or for other reasons related to cost and effectiveness.